Roller guide shoe for elevators



Feb. 21, 1950 R. RISSLER ROLLER GUIDE SHOE FOR ELEVATORS Filed May 22, 1948 r k R j o 5 m 2 E 1 me m 5 a my 9 a T 3 Z 35 3 U y 3 5 3 e 4 W 9 0 4 B 7 l I e 9 3 3 a a 6 .i l j v I fi a n A 3 T W w P 7 Q bill I I a l 7 a 5 w WITNESSES:

ATTORNEY Patented Feb. 21, 1950 :UNITiED P-rSTATES OFFICE ROLLER'GUIDE sizii z oa nnnvmons LB1'lnillS"-R:" Ris sler," -Hh0kl1S,"-'=N.r J assignor to i westinghouserElectr ic Corporation,EastPittsbufghfPa a corporationof Pennsylvania Application May 22, 1948-SeriaiFN 281542 of guide rails which guide an elevator car for; -movementrz-in1- a vertical-direction. The elevator car hasguide shoes associated therewith-which I coop'erate "with lthe guide rails for guiding purfiposes. Similar: guiderrrails and: guide shoes. are .emploBierizfion guiding the elevator counterweight for movement a-vertical direction.

iAn'elevator-guide shoe of-the rolleratype may employ-three rollers for engaging surfaces of the ,associatedguiderailb Oneof the rollers engages the'face-s-urface of the .guiderail whereas the remaining rtwo. rollers-l engage the side surfaces =of-the rail. 1 It-is--assurnedthat a conventional T- sh-aped guide :railds employed.

1:111 accordance-with the invention, an elevator vvguide shoeincludes a=-base:-structure. Each-roller iiszmounted on a shaft for rotation. relativeto a :shaftyand the lshaftwis secured to-the base structure through a body constructed of sound-insuylati ngtmaterial. :If the rollerr-has a sound-insu- Jl'ating rim, "the sound-insulating bodyra'cts'din series with :the rim to assure adequate suppresssiornofsound-or noise -iresulting-from movement of theselevatoncar rel ative to theassociatedguide rails. Conveniently, two axially-spaced bodies constructed; of sound-insulating material may be employed iforlthe' 'shaft ofeach' roller.

'Variousmaterialsmay'be -employedfor sound- "insulat'ingl purposes. For example, many resins such as phenolic resins have. a substantial degree -ofsrsound insulati-ng properties. However, elas- -tomers such as =-n'atural or synthetic-rubber are -particula rly suitable 'f0r='-s0und'insulatingpurposes. 52in apreferred embodiment of the invention, an adjustable compressor is 'provided'for adjustably compressing or tuning the elastomer for optimum noise suppression. "TheeXacttuning required may Vary'for different" elevator installations.

' If the ax-is of rotation of a rolleris' parallel =to=anddisplaced-from the axis of its supporting shaft-and the shaft-"is releasably clamped by noise-insulatingmaterial to the" base structure, the shaft'may be rotated to adjust the position of the roller'with respect tothe associated guide rail surface. Also, anelastomersound-insulating spring may be employed for resiliently biasing the face roller towards the associatedguide rail.

' It is, therefore, an object. ofl the invention -to provide-as guidem-roller. for-an :elevatorv system.-

.-=which ;-.is secured -to.-:- a base -structure through "soundeinsulating': material.

alt :is; a further .obiect of the invention to pro- I e -aigu-ide roller for elevator systems which '5 is .seeured tor a base structure through sound-ins-sulati-ng fmaterial oapableof sbeing -=-adjustably -compressedor tuned'for optimumnoisesuppres- 5 411, is zan v-ad'ditional: object-of the inventionto wprovidel a; guide roller for an elevator system which: is-imountedeccentrically with respect .110 nasupporting shaft-,thelshaft-being secured releasl' ably :to i a; base structure through an elastomer emind-insulatingmaterial.

i Itaisstilli another objectof- :the .-.inventlonmto :providea apgu-ide roller for an. elevator system wherein Ian: elastomermsound-insulatinglspringis employedlfor biasingthe roller againstwan asso- -ciated-guide surf-ace.

l-lIt is also .arlv obj ectof the-invention to. provide a roller guide shoe for an elevator system wherein aroller havinga rim of elastomer sound-insu- -l-ating rmaterial -is --secured .to.- abase structure EthroughV a body. -constructed of soundeinsulating rnateri-al.

It is astill: .iurther object .lofzthe' invention 1 to provide an elevator. system wherein aguide rail -.-has'associated-therewitha guide shoe comprisi-ngtwouside rollers and; awf ace mollerfleaclrprovided with a rim of sound insulating material, wand-each secured to a base structure through two bodies constr-uctedl-of soundeinsulating. material vvhichzrareespaced .in a direction parallel .to the taxis of the associated-roller.

VOther-objects of-theinventionwill be apparent --.from-the iollowing-description taken -in conjunction. with the accompanying drawings, in which:

t Figure l is. a view-in elevation, with parts bro- 1 ken raway, ofaan elevator .system embodyingthe invention;

, Figs 2=is-a view in side elevation, with "parts broken 'away,l of- -an elevatorguide shoe embody-.

ling thetinvention;

\ 'Figw 3-is. a-view in-ltop plan, with parts broken away-,showing the guide shoe of Fig. 2 associated -=Wil3h a. guide rail;

r- Fig; 4-is-ra='vieww-in'rear elevation, with parts -br0ken away, of the guide shoe illustrated. in Fig 2;

.laway showingl a modified rollerygui-deeshoesembodying 'the invention and Fig.- 6 .is .a view in=-side elevation, with parts broken-awaywof the guide shoe--illustrated-.in

llshers of Sandusky, Ohio.

been found satisfactory.

Referring to the drawings, Figure 1 shows an elevator system which includes two conventional parallel guide rails l and 3. These guide rails are installed in an elevator hatchway or hoistway for the purpose of guiding a sling 5 in a vertical direction. The sling may support a counterweight or an elevator car, as desired, but it will be assumed for the purpose of discussion that the sling 5 is employed to support an elevator car i. The sling 5 is secured to the end of ropes or cables 9 which have forces applied thereto in a conventional manner for moving the-elevator car.-

The sling 5 is guided with respect to the guide which is perpendicular to the side surfaces. The

guide shoe l3 includes a roller IQ for engaging the side surface 3a. For quiet and smooth performance and for long life, the roller 19 is pro- "vided with a resilient rim which may be part of "a resilient disc 2!. obtained from a roller employing resilient mate- Excellent results have been rial similar to that disclosed in my copending application, Serial No. 758,087, filed June 30, 1947.

In accordance with the teachings of the foregoing application, theresilient material may be con- 'structed from a cellular matrix or filler such as nylon, silk or rayon. Alternatively, a metal cloth suchas a brass cloth could be employed. In a preferred embodiment, the matrix is formed by a plurality of laminations in the form of discs 23 indicated only in Fig. 2 for part of the roller IQ of woven fabric, such as cotton sheeting or canvas. These discs are disposed in side by side relation in alignment and transverse to the axis of the roller.

The layers of cotton sheeting or canvas are bound together by an elastomer. Natural rubber has been found satisfactory for the elastomer, but it is to be understood that other elastomers such as synthetic rubbers are also suitable for binders and a number of suchrubbers will be found listed on page 695 of the Hand-bookv of Chemistry by M. A. Lange, 1944, published by Handbook Pub- A chloroprene polymer which is available on the market under the trade name neoprene is an example of a suitable synthetic rubber. .The elastomer Buna S also may be employed and is listed in the aforesaid handbook. A disc wherein the filler represents 50% to 90% of the total weight of the disc has Particularly good results are obtained for a disc having a weight of cotton canvas or sheeting approximately 70% of the weight of the complete disc. The elastomer flows through the fabric layers to bond the threads "to each other throughout the disc and if of the vulcanizing type may be vulcanized with the j woven fabric under pressure. The elastomer may be'vulcanized and cured to a hardness of prefera b-ly 35 durometer or greater. The procedure may be similar to that employed for manufacturing rubber fabric belting. After vulcanization the disc 2| may be assembled between rigid discs 25 and 21 and secured thereto in any suitable manner by means of rivets 28 (Fig. 4). Good results have been obtained from a disc 2! formed of an elastomersuch as natural rubber having a comminuted filler embedded therein. In order to decrease the weight and inertia. of the roller, the

discs 25 and 2! may be constructed of aluminum or other suitable lightweight material.

The disc 2! has a substantial cylindrical surface and is constructed to flatten slightly for the purpose of distributing the load over a substantial portion of the surface 322- of the guide rail. However, the flattening is not such that a bead is formed adjacent the'guide rail during rolling of the roller thereover. The edges of the disc may be beveled.

The radial distance A between the circumference of the discs 25 and 2'! and that of the disc 2| is important for optimum roller life. As the roller moves over the surfaces of the guide rail, the material of the disc 2| is subjected to local movement as it approaches the guide rail and leaves the guide rail. The discs 25 and 21 are proportioned to confine this local movement to a predetermined portion of the disc or rim represented by the reference character A. For a roller having a diameter of D inches, the dimension A may be of the order of /g inches shaft 29 is secured to a base structure 3| through a body of sound-insulating material 3.3.

As previously pointed out, the sound-insulating material may comprise a resin, such as a phenolic resin. Preferably, however, thematerial is an elastomer, such as natural or synthetic rubber. Synthetic rubbers similar to those listed in the aforesaid handbook may be employed, but good results have been obtained from natural rubber. The body 33 may be adhesively bonded to the shaft 29 and to the base structure 3! but in a preferred embodiment of the invention, the body is adjustably compressed between the shaft and the base structure. The body 33 may take the form of a bushing which is slipped over the shaft 29. This bushing is snugly received within a cup 35 which is formed in .the base structure 31. The cup has an end wall which is provided with an aperture 3'! permitting passage of the shaft therethrough.

, Although asingle body 33 may be employed for the shaft 29, it has been found advantageous to provide a second sound-insulating body 39 which is similar to the body 33. The body 39 is snugly received within a cup 4i formed in the base structure 35. The cups 35, and 4! are similar in con structicn but have their end walls adjacent each other. The spaced bodies 33 and 39 permit the utilization of small bodies which adequately support the shaft 29 and which may be readily compressed. I

The compression of the bodies 33 and 39 is effected by meansof two collars 43 and 45. The collar 43 may be rigidly secured to the shaft-23, whereas the collar 45 is movable with respect to the shaft. The collar 45 conveniently may take the form of a washer. The end of the shaft 29 is provided with threads 41 for threaded reception of a nut 49. By actuation of the nut 49, the bodies 33 and 39 may be compressed adjustably to the desired value. I It has been found that the noise or sound suppressing properties of the bodies 33 and 39 dependon the compression thereof. By proper adjustment of the nut 49 over a suitable range, the

has clearance from the shaft 29'and from. the collars 43 and 45. The only connection between the shaft 29 and the base structure is through the sound-insulating bodies 33 and 39;. These bodies act in series with the sound insulating disc 2| between the elevator car and the guide rails to provide effective suppression of vibration, sound or noise, resulting from the movement of the elevator car with respect. to the associated guide rails. If constructed from elastomers the resulting resilience of the bodies and the disc facilitate good tracking. of the roller on a rail having irregularities. Also the dampening properties of elastomers such as rubber help to reduce rapidly the amplitude of any vibration.

Itwill be observed that the shaft 29 is in effect releasably clamped to the base structure 3| by manipulation of the nut 49. This permits a simple adjustment of the roller. l9 with respect the roller |9 to approach or recede from the guide rail 3. Consequently, the shaft 29 may be rotated in any suitable manner as by a screw driver inserted in the slot 53. to adjust the position of the roller with respect to the guide rail prior to the compression of the bodies 33' and 39.

The guide shoe includes a second roller 55 for engaging the side surface. 3a of the guide rail. This roller is mounted on a shaft 51' which is secured to the base structure 3| through soundinsulating bushings 5'9 and 9|. similar in construction to the roller l9, it is mounted on the shaft 51 in the same manner whereby the roller l9 is mounted on the shaft 29, and the shaft 51 is secured to the base structure 3| in the same manner whereby the shaft 29 is secured to the base structure. A further discussion of the roller 55 and its associated parts is believed to be unnecessary. It will be observed that the shafts 29 and 51- have axes which are parallel to each other and to the side surfaces 3a and 317. These axes are perpendicular to the direction of travel of the guide shoe in the elevator hatch.

A face roller 63 is provided for engaging the face surface of the guide rail. This face roller is similar in construction to the rollers and Hi. The roller 93 is mounted for rotation with respect to a shaft 65 which is secured to one end of a bell-crank lever 61 in any suitable manner, as-by a nut 69 which engages the threaded end of the shaft. The bell-cranklever 61 is mounted for pivotal movement with respect to the base structure 3| about the axis of a rod 1 l. The. lever is secured totherod in any suitable manner as by providing the lever with spaced apertured lugs 3 and 15 (Fig. 4) for receiving the rod. The lever may be releasably secured to the rod H by means of a removable key H which is a press fit within aligned openingsprovided in the lever and.

the rod.

sounddnsulating bushings l9 and 8| are provided for the rod H and these bushings are similar tothebushings 33 andv 39. of Fig. 3. The bushings19v and 8| are positioned within spaced cups The roller 55. is

pletely sound-insulated from the base structure 83' and 85 formed in the base structure 3| in erbactly the same manner employed for mounting the bushings 33 and 39 in their associated cups. Although a nut may be employed at only one end of the rod 1|, preferably both ends of the rod are threaded for reception of separate nuts 81' and 89. Collars 81a and 89a are interposed, respectively, between the nuts 81 and 89 and their associated bushings; These collars may comprise washers having openings. snugly and slidably receiving the rod and may have. outer diameters slightly less than the. outer diameters. of'their associated sound-insulating bushings. By employing two nuts, the. roller 63 may be accurately centered with respect to the face surface of the guide rail.

It will be understood that. the bushings 19 and 8|. are compressed by manipulation of the nuts 8'! and 89. Since the rotation of the. rod H. with respect to the base structure need not be. large, such rotation is effected without any sliding movement between the rod. H and its associated bushings I9 and 8| or between the bushings and the base structure 3|- Rotation of the rod H with respect to the base structure merely torsionally flexes or changes the stress in the bushings.

The roller 63'is further resiliently biased against its associated face surface 30 of the guide rail by means of a spring 9| acting between an: end of the bell-crank 61 and the base structure 3|. If this spring were constructed of a sound-transmitting material such assteel, it. would establish a sound-conducting path which would bypass the bushings 19 and 8|. For this" and other reasons, the spring 9! is constructed of asound-insulating material which may be similar to that employed for the bushings 1-9: and BI; In a specific embodiment illustrated in Figs. 2, 3 and 4, the spring is in the form of a tube constructed of an elastomer such as natural or synthetic rubber. One

end of the tube rests on a platform established by the structure 3| and the remaining end of the tube engages the end of the bell crank 61 which is remote from the roller 63. By inspection of the drawings, it will be clear that the spring 9| resiliently urges the roller 63 toward the guide surface 30 of the guide rail. In order to prevent excessive movement of the roller 63, a rigid stop 93 is introduced between the bell crank and the associated base structure 3-|-. Conveniently, the rigid stop 93 may be constructed as a protuberance. which extends from the base structure 3| within the tubular spring 9|. .The exposed end of the protuberance forming the stop the bell crank never touches the protuberance 93'.

From the foregoing discussion it isclear that each of the shafts or rods 29", 5 1 and TI is com- 3|. Each of the nuts for compressing the soundinsulating material maybe locked in any suitable manner as by means of cotter pins 95.

The provision. of the elastomer bushings assures a compact and noise tree structure. The elastomer bushings permit eccentric adjustment of the rollers I9 and 55 for the reason that the bushings releasably clamp the shafts 29 and 57 At the same time, the bushings take up all play between the associated parts.

spring, the rollers readily follow small. irregularirties in the guide rails without transmitting appreciable noise or vibration. between the elevator car and. the guide. rails. Moreover; as: previously By employing. elastomer bushings, roller rims and. an. elastomer pointed out, the elastomer material preferably employed acts effectively to damp vibration. Furthermore, the bushings may have their compression adjusted to provide optimum sound insulation for any desired elevator installation. The bushings require no lubrication and little, if any, servicing. The entire guide shoe is unusually compact and trouble free.

It will be understood that the base structure 3! may be secured to the sling 5 in any suitable manner. For example, in Fig. 3 openings 9'! are provided in the basestructure through which machine screws (not shown) may be introduced for the purpose of attaching the guide shoe to the sling.

Although the same guide shoe may be employed for both the elevator car and for the counterweight, the modified construction of Figs. 5 and 6 has been found suitable for the counterweight. In these figures, a guide shoe III! is provided which includes two rollers I03 and I05 which correspond in construction and purpose to the rollers I 9 and 55 of Figures 2,; 3 and 4' and which are mounted in exactly the same manner with respect to the base structure .IiJ'I of the guide shoe IIJI. For example, the roller I05 is provided with a shaft I09 which corresponds to the shaft 5! of Fig. 3, elastomer bushings III and H3 which correspond to the bushings $I and 59 of Fig. 3, and a nut II5 which coacts with suitable collars IZI and I23 for placing the bushings under compression. In some cases it may be unnecessary to provide an eccentric adjustment for the roller I05 and in such cases, the axis of the roller I65 may be the axis of the shaft I09.

The guide shoe Ill! also includes a face roller I 25 which corresponds to the face roller 53 of Fig. 3 and which is similarly constructed. Since more space usually is available adjacent the counterweight for the face roller I25, this roller may be larger in diameterthan the rollers I03 and I05.

For the counterweight the provision of a biased lever for the face roller I25 generally is not required. Consequently, the roller I25 may be mounted on the base structure In! in substantially the same manner by which the rollers I03 and I05 are mounted on the base structure. Referring to Fig. 5, it will be observed that the roller I25 is mounted for rotation about a shaft I29 which has axially-spaced sound-insulating bushings I3I and I33 associated therewith. These bushings are received in cups I35 and I3? formed in the base structure III! in the same manner whereby the bushings III and IE3 are received in their associated cups. The shaft I 29 is threaded at each end for reception of nuts I39 and I II which may be actuated to force collars .or washers I43 and I 45 against the bushings to compress the bushings. By employing two nuts, the roller I25 may be accurately centered with respect to the associated face surface of the guide rail 3A.

It will be understood that the base structure III? is secured to the sling of the counterweight in a position to hold the face roller I25 securely against the associated face surface of the guide rail 3A.

As a general rule, it is desirable to provide additional limit stops for the roller guide shoes. For example, in Fig. 3, it will be observed that the base structure 3| is provided with lips 3IA and 3IB which define a notch 3IC for reception of a portion of the guide rail 3. Under normal conditions of operation, the guide rail never touches the bounding surfaces of the notch. However, should damage occur to one'or more of the roller assemblies, the maximum movement of the guide shoe I3 with respect to the guide rail 3 is limited by the clearance between the bounding surfaces of the notch 3IC for each roller guide shoe and the associated guide rail. A similar notch INC is provided for the embodiment of Figs. 5 and 6.

Although the invention has been described with respect to certain specific embodiments thereof, numerous modifications falling within the spirit and scope of the invention are possible.

I claim as my invention:

1. In a roller guide assembly for elevator systems, a support member, a roller mounted on the support member for rotation relative thereto, a base structure, and a fastener securing the support member to the base structure, the fastener including a sound-insulating elastomer body, said support member, sound-insulating body and base structure being nested together with the body intermediate the member and the structure to impede transmission of noise therebetween, the axes of the roller and the noise-insulating body being substantially parallel.

2. A guide assembly as defined in claim 1 wherein the axes are spaced from each other, and an element constructed of a sound-insulating elastomer for yieldably biasing the roller in a predetermined direction about the axis of the sound-insulating body. l

3. In a guide assembly for elevator systems, a base structure, an elastomer body, an elevator guide shoe secured to the base structure through said elastomer body, and an adjustable compressor operable for adjusting the compression of the elastomer body.

4. In a roller guide assembly for elevator sysstems, a support member including a shaft, a roller mounted on the support member for rotation relative to the support member about a first axis displaced from the shaft axis, said axes being substantially parallel, a base structure, a fastener for securing the support member to thebase structure, said fastener comprising a sound-insulating body for receiving the shaft and insulating the shaft from the base structure, and an adjustable compressor for compressing the elastomer to secure releasably the shaft in the elastomer, said compressor being adjustable for varying the compression of the elastomer over a substantial range.

5. In a roller guide assembly for elevator systems, a support member, a roller having a rim constructed of a sound-insulating material, said roller being mounted on the support member for rotation relative to the support member, a base structure, securing mechanism for securing the support member to the base structure, said securing mechanism comprising a body of a soundinsulating elastomer material interposed between the support member and the base structure and insulating the support member from the base structure.

6. A roller guide assembly as defined in claim 5 wherein the securing mechanism includes an adjuster for adjusting the compression of the body, whereby the sound insulation of the body may be adjusted to an optimum value for a particular installation of the guide assembly.

7. A roller guide assembly for elevator systems comprising a support member, a roller mounted on the support member for rotation with respect thereto, a base structure, and a fastener including a pair of elastomer bodies spaced along an axis parallel to the axis of rotation of the roller for securing the support memher to the base structure.

8. A roller guide assembly as defined in claim '7 in combination with an adjustable compressor operable for adjusting the compression of the elastomer bodies over a substantial range.

9. A roller guide assembly as defined in claim 7 wherein the support member includes a shaft having portions nested within the respective elastomer bodies, the shaft axis being displaced from and parallel to the axis of rotation of the roller, and a compressor for compressing the elastomer bodies to secure releasably the shaft therein.

10. A roller guide assembly for elevator systems comprising a shaft, a roller mounted on the shaft for rotation relative thereto about an axis parallel to the shaft axis, a pair of sound-insulating, axially-spaced elastomer bushings surrounding said shaft, a base structure having a pair of spaced cups snugly receiving said bushings, said cups having their end walls adjacent each other and apertured to permit passage therethrough of the shaft, a pair of spaced collars disposed on the shaft for engaging the exposed ends of the bushings, one of said collars being adjustable relative to the other of said collar for compressing the bushings to clamp the shaft releasably and resiliently to the base structure.

11. A roller guide assembly as definedin claim 10 wherein the axes of the shaft and of the roller rotation are spaced.

12. A roller guide assembly as defined in claim 11 in combination with an elastomer spring for biasing the roller relative to the base structure in a predetermined direction about the shaft axis.

13. A roller guide assembly as defined in claim 10 wherein the roller has a sound-insulating elastomer rim.

14. An elevator system comprising a guide rail having a face surface and a pair of side surfaces perpendicular to the face surface, an elevator car to be guided along said rail, and an elevator guide shoe comprising a pair of side rollers having elastomer rims respectively engaging said side surfaces for tracking along said surfaces, a separate shaft mounting each of said rollers for rotation about an axis parallel to the shaft axis and to the side surfaces, a face roller having an elastomer rim engaging said face surface for tracking along the face surface, a shaft mounting the face roller for rotation about an axis parallel to the axis of the last-named shaft and the face surface, a separate pair of axially spaced elastomer soundinsulating bushings surrounding each of the shafts, a base structure having a separate portion substantially surrounding each of the bushings, and compressors for compressing the bushings between the base structure and the associated shafts to secure the shafts resiliently to the base structure.

15. An elevator system as defined in claim 14 in combination with an elastomer spring for resiliently urging the face roller about the axis of the shaft supporting the face roller towards the guide rail, the axis of each of the shafts being spaced from the axis of rotation of the associated roller supported by the shaft.

16. In an elevator guide shoe roller, a disc comprising an elastomer, and a rigid disc positioned on each side of the elastomer disc concentrically therewith, said rigid discs being secured to each other, said elastomer disc having a diameter D larger than the diameters of the rigid discs to provide a free rim portion having a radial dimension of substantially 17. A roller guide assembly for elevator systems having a guide rail, said guide assembly comprising a pair of side rollers having spaced, parallel axes, said rollers being disposed in substantially a common plane and being spaced from each other, a face roller disposed substantially on one side of, and substantially perpendicular to, said common plane, each of the rollers having an elastomer rim, said rollers defining a, pocket for reception of a guide rail, a separate support for each of the rollers, each of the supports mounting the-associated roller for rotation about the axis of such associated roller, a base structure, and securing mechanism comprising sound-insulating elastomer for securing the supports to the base structure, said elastomer insulating the base structure from said supports.

18. A roller guide assembly as claimed in claim 1'7 wherein the securing mechanism mounts the face roller for rotation about an axis substantially parallel to, and spaced from, the axis of the face roller, said securing mechanism including an elastomer spring for biasing the face roller relative to the base structure towards said pocket, said elastomer spring constituting a substantially non-conductive sound path between the face roller and the base structure.

19. A roller guide assembly as defined in claim 17 wherein each of the supports comprises a shaft, and the sound-insulating elastomer comprises a pair of spaced elastomer bushings surrounding each of said shafts. I

20. A roller guide assembly as defined in claim 17 wherein the securing means includes adjustable compressors for adjusting the compression of the elastomer intermediate the supports and the base structure to provide optimum sound suppression of noise of any desired frequency within a substantial range of frequencies.

21. A roller guide assembly as defined in claim 19 wherein at least one of the rollers is eccentrically mounted on the associated shaft, and the securing means includes releasable means for compressing the elastomer bushings for said associated shaft, whereby the associated shaft may be adjusted angularly about its axis to adjust the position of the eccentrically-mounted roller.

LENNIUS R. RISSLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,854,976 Brady Apr. 19, 1932 2,100,169 Norton Nov. 23, 1937 

